A cluster tool includes processing chambers, internal robots to manipulate wafers, and load lock chambers where wafer exchanges take place from the load lock chamber to the transfer chamber. The transfer chamber is held at a low vacuum pressure. The load lock chamber is connected to the transfer chamber by a valve. The load lock chamber receives a wafer from atmospheric pressure. The vacuum pressure of the transfer chamber/buffer will increase once it is opened to receive a wafer. Thereafter, the transfer chamber will be pumped by a vacuum pump to return to the vacuum pressure.
Sometimes long recovery times may be needed for the transfer chamber to return to the vacuum pressure, once the transfer chamber is closed and receives the wafer from the load lock chamber. Such long recovery times can be detrimental to throughput. A recovery time associated with the transfer chamber/buffer returning to a low vacuum pressure should be conceivably as short as possible so manufacturing deposition processes can occur in vacuum conditions.
Additionally, cluster tools can include chambers with several different valve separation configurations. Different chambers can be separated by valves to maintain vacuum conditions, such as a load lock chamber and a transfer chamber. Valve arrangements can be costly. These configurations can also include an isolation valve that separates a vacuum pump from a chamber, such as a transfer chamber, or a valve that separates a rough pump from a load lock chamber. Numerous sets of valves are costly and can drive up the overall cost of the cluster tool. Moreover, each valve is often controlled in a precise manner to open and close to affect a wafer transfer. Valve control is also costly and may increase the overall operation cost of the cluster tool.
Further, regeneration operations often can result in a suspension of the manufacturing processing to remove materials from a primary pumping surface of a cryogenic pump. These regeneration operations can also decrease throughput of the cluster tool.